1. Field of the Invention
The invention relates to a new and improved crank and a base of a treading exercise apparatus, and more particularly, to a single crank having two supporting shafts that are rotatably and coaxially positioned on corresponding posts of a base. Since the unbalanced force created by the treading movement on the crank is effectively supported, a stable treading movement can be achieved. Meanwhile, the related components can be well protected from damage, thereby elongating the service life thereof.
2. Description of the Related Art
The so-called treading exercise apparatuses include all in-place exercise means for treading movement. This apparatus is well known so that no further descriptions of its basic configuration and operational principles are given hereinafter. However, the local components of the crank related to the invention are described as follows:
Referring to FIG. 2, the assembly of the crank 10 and the base 11 of a conventional treading exercise apparatus is shown. The crank is constructed as a horizontal shaft 12 in the middle thereof on which a bearing 13, a bushing 14 and a resistance flywheel 15 (or toothed plate) are received so that the crank 10 rotates on a middle post 16 of the base 11. Meanwhile, both sides of the first shaft 12 are constructed as a correspondingly symmetric L-shaped treadle rod 25 relative to the shaft 21 on which a treadle pad 26 is rotatably received for treading movement in alternating succession.
The above-mentioned configuration of the crank 10 and the base 11 has been used for over decades and doesn""t have tremendous change. However, a rubbing sound is apparently created from the position of the crank 10 after a long period of usage. For more serious situation, the crank 10 operates with difficulties. Even when the bearing 13 and the bushing 14 of the crank 10 are replaced by new ones or oiled, people can be free of mechanical noise only for a short period. Thereafter, the noise arises again, thereby giving much trouble to the user.
In fact, the above-mentioned problem arises due to the unbalanced application of force on both sides of the crank when the operator uses both feet to perform treading movement (that is, one foot exerts force while the other is in relaxed state. Of course, the crank is operated by this principle.). If the load of the crank 10 is supported only by the horizontal shaft 12 and the middle post 16 of the base 11, the bearing 13 and the bushing 14 must be considerably loaded.
Thus, it""s inevitable that the bearing 13 and the bushing 14 are seriously damaged after a long period of usage. For the serious situation, noise arises; for the more serious situation, the bearing 13 and the axle hole of the middle post 16 are worn off. At this time, it""s also useless to replace with an excellent bearing 13.
An object of the invention is to eliminate the above-mentioned drawbacks and to provide a crank and a base of a treading exercise apparatus in which a single crank is specially designed to have two supporting shafts that are rotatably and coaxially positioned on corresponding posts of a base. Since the unbalanced force created by the treading movement on the crank is effectively supported, a stable treading movement can be achieved. Meanwhile, the related components can be well protected from damage, thereby elongating the service life thereof.